Hollow drill sharpener



Dec. 18, 1962 B. F. DlRZlUS HOLLOW DRILL SHARPENER Filed Dec. 14, 1961 I El@ ite rates My invention relates to a Sharpener for a drill in the form of a hollow tube with an open top. Such drills used for cutting holes in paper have top edges that frequently must be sharpened.

Heretofore, Sharpeners for such hollow tube drills created rough top edges with burrs. It was then necessary to remove these rough edges and burrs by a honing operation. This often resulted in uneven edges, increased wear, breakage, and replacement with delay and added cost.

It is among the objects of my invention to solve these problems and remove these objectionable characteristics; to provide a Sharpener with a bushing for supporting the hollow tube being sharpened immediately back to the sharpened edges so as to prevent the metal from bending over and forming burrs, thereby eliminating the secondary honing operation; to supply a Sharpener that will insure razor sharp cutting edges free of roughness; to create a Sharpener having graduations for control so that the user may determine in advance how much metal is to be removed from the tube tool being sharpened, and to provide a structure for centering the Sharpener and the tube tool being sharpened.

My invention contemplates such other objects, advantages and capabilities as will later more fully appear and which are inherently possessed by my invention.

While l have shown in the accompanying drawings a preferred form of my invention, yet it is to be understood that the same is susceptible of modification and change without departing from the spirit of my invention.

Referring to the drawings, FIG. l 4is a side elevational view of my hollow drill Sharpener partly in section; FIG. 2 is an end elevational view on line 2 2 of FIG. l partly in section; FIG. 3 is an enlarged sectional view showing the adjusting means; FIG. 4 is a side view of the cutting member with the sleeve bushing in section; FIG. 5 is a front View of my cutting member; FIG. 6 is a detailed view of the assembly of the cutting member and bushing partly in section; FIG. 7 is a detailed view of the hollow drill to be sharpened; and FIG. 8 is an end view of the same.

The embodiment selected to illustrate my invention comprises a housing 1G, preferably of aluminum and having a body portion 11 and a base 12. Extending laterally through body portion 11 is a bore 16 within which is shrunk a sleeve 13, preferably of steel. In sleeve 13 is a lock ring 14 which acts as a stop member for bushing 15. Bushing 15 has a center hole 18 extending therethrough and a `downwardly and inwardly angled countersink 19, preferably at a 90 included angle, leading to hole 18.

My cutting member has a single ute countersink 21, preferably at an 82 included angle. This included angle may vary between 68 and 89. The cutting edge of my cutting member 20 is radially relieved. A sleeve bushing 22 engages the shank 23 of cutting member 2li and extends beyond bore 16. Sleeve 13 extends beyond body portion 11 and is screw threaded to receive and hold a screw threaded cap 24, which bears against sleeve bushing 22 so as to hold cutting member 20 against bushing 15. Because of the different included angles of the cutting member and the bushing, cutting member 20 bears against bushing 15 only at one point, indicated in FIG. 6 of the drawing as 25.

Body portion 11 of housing 1t) has a vertical slot 26,

within which is rotatably mounted adjusting ring 27 having interior screw threads 28, to receive screw threads 29 on hollow microguide bushing 30.

Adjusting ring 27 has spaced graduations in thousandths of an inch with markings. Microguide bushing 30 has an end portion 31 which is not screw threaded, and which extends beyond housing 10. Bushing 30 has a key way 32 engaging pin 33 in body portion 11 to prevent undesired rotation.

A holder 34 has a spindle 35 for receiving the hollow drill or tube tool 17 to be sharpened, and suitable means for removable attachment of the tube tool thereto. Said holder 34 has a drive disc 36 attached to one end of spindle 35. Handle 37 is attached to disc 36.

In sleeve 13 an opening 38 is provided communicating with hole 39 in housing 10 to permit the chips cut off from the tube tool during the sharpening, to fallout.

In use, the user turns adjusting ring 27 to the graduation determined for the desired amount of removal of metal from the tube tool to be sharpened. The user then grasps disc 36 and inserts the tube tool to be sharpened held by spindle 35 into guide `bushing 30 until disc 36 abuts the end of bushing 3d. The user then grasps handle 37 and rotates the assembly until the sharpening of the tube tool has been completed.

The hollow drill or tube tool being sharpened is supported by bushing 15 right back of the cutting edge of cutting member Ztl so as to prevent the bending over of the metal on the tube tool and the forming of burrs. This insures the sharpening of a razor like edge on the tube tool. There is no need for honing burrs or removing ragged edges and no delays due to breakage and replacement.

Having thus described my invention, I claim:

l. A hollow drill Sharpener comprising a housing having a bore therethrough, a sleeve mounted in the bore of said housing, and having a stop means, a bushing mounted within said sleeve and against said stop means, said bushing having an opening theretlnough, and a countersink communicating with said opening, said countersink at a desired angle, a cutting member mounted in said sleeve and having a single ute countersink, said countersink at a different angle than the angle of the countersink of said sleeve, said cutting member bearing against said bushing at one point, a cap for removably closing an end of the bore of said housing, and a holder for removably holding a hollow drill to be sharpened, said holder adapted for insertion of the hollow drill to be sharpened, through and into the other end of the bore of the housing and through said bushing and against said cutting member, said holder adapted to be rotated so that the hollow drill may be sharpened on the cutting member as it is supported by the bushing immediately back of the cutting edge of the cutting member during sharpening to prevent burring, said sleeve and said hous` ing having communicating bottom openings for the passage of chips from the sharpened hollow drill.

2. A hollow drill Sharpener comprising a housing having a bore therethrough, a sleeve mounted in the bore of said housing, and having a stop means, a bushing mounted within said sleeve and against said stop means, said bushing having an opening therethrough, and a countersink communicating with said opening, said countersink at a desired angle, a cutting member mounted in said sleeve and having a single flute countersinl-, said countersink at a dierent angle than the angle of the countersink of said sleeve, said cutting member bearing against said bushing at one point, a cap for removably closing an end of the bore of said housing, a hollow micro guide bushing extending into the other end of the bore of the housing, a holder for removably holding a hollow drill to be sharpened, said holder adapted for insertion of the hollow drill to be sharpened, through and into said micro guide bushing and through said first mentioned'bushing and against said cutting member, said holder adapted to be rotated so that the hollow drill may be sharpened on the cutting member as it is supported by the bushing immediately back of the cutting edge of the cutting member during sharpening to prevent burring, said sleeve and said housing having communieating bottom openings for the passage of chips from the sharpened hollow drill, and an adjusting ring rotatably mounted on said micro guide bushing for moving the micro guide bushing a desired distance with relation to the bore so as to guide the holder with its attached hollow drill to be sharpened so that a predetermined amount of the hollow drill will be removed by said cutting member during the sharpening of the hollow drill.

3. In a hollow drill Sharpener, a bushing having an opening therethrough, and a countersink communicating with the'opening, said countersink at a desired angle, a cutting member having a single flutecountersink, said countersink at a different angle than the countersink of said bushing, the countersink of said cutting member bearing against the countersink of said bushing at one point, a holder adapted to removably hold a hollow drill to be sharpened and guide it through the opening in said bushing and against said cutting member, said bushing supporting the hollow drill immediately back of the cutting edge of the cutting member during the sharpening by said cutting member to prevent -burring.

bore therethrough, a cutting member and a bushing positioned within the bore, said bushing having an opening therethrough, a hollow micro guide bushing mounted in thebore at its opposite end and extending beyond said housing, a graduated ring rotatably mounted on said microguide bushing and a holder having an outer disc of larger diameter than said hollow micro guide bushing and an inner portion for removably holding a hollow drill to be sharpened, said inner portion being of smaller diameter than said hollow micro guide bushing and the hollow drill to be sharpened being of smaller diameter than the opening in said rst mentioned bushing, so that it may extend therethrough to said cutting member, said ring adapted upon rotation to move said micro guide! bushing farther away from or nearer to the end of said housing so that as said outer disc contacts the outer end of said hollow micro guide bushing, said inner portion of said holder may so advance within said hollow micro guide bushing that its attached hollow drill will advance through the opening of said rst mentioned bushing for a predetermined amount of removal therefrom by said cutting member during theV sharpening operation.

Porter June 8, 1909 Gylleck Dec. 27, 1938 

